The overall objective of this research is an improvement of man-machine-communication via two-dimensional languages. The goal of this project is an improvement in the speed and ease with which biomedical researchers can draw, recognize, and compare structural formulae displayed on the graphics terminal of on-line biomedical computer systems. This objective can be accomplished by defining a significant subset of the conventional diagrams used by chemists and pharmacologists to represent molecular structure. Linguistic techniques that will be investigated as a means to this definition include constituent-structure, syndeictic and transformational analysis. The formal mechanisms used for definition will be array grammars and graph grammars. Semantic rules corresponding to syntactic rules will be defined. General but efficient parsing algorithms for the grammars constructed will be sought. Syntax-directed-translation will be used to map structural formulae into connection tables and vice versa. More efficient methods for display of standardized structure diagrams will be developed by defining the morphology of standardized ring structures and use of inherited and synthesized translation techniques.